Introduction

Trigeminal Neuralgia (TN), or "Tic Douloureux" is a disease of the fifth cranial nerve that results in intermittent, shooting pain in the face. Many people describe it as shooting, stabbing or electric shock like pains.  The pain can be spontaneous or precipitated by light touch to the face or to a trigger point – usually on the face or in the mouth.  People can usually remember the first time they experienced this pain because of its severity.

Trigeminal Neuralgia can occur at any age, but usually has its onset in individuals over fifty. It is common for the pain of Trigeminal Neuralgia to come and go spontaneously (frequently referred to as waxing and waning), which often makes it difficult to know whether any specific treatment is beneficial.

In most cases of Trigeminal Neuralgia, an enlarged looping artery or vein is found to be pressing on the nerve anywhere along its length.  The most common site tends to be where the nerve leaves the brain stem at the base of the brain. Other less frequent causes can be a brain tumor or a vascular malformation or multiple sclerosis.  A MRI scan can identify the existence of these possible causes.

Unfortunately, over time the pain of Trigeminal Neuralgia usually becomes more severe and more frequent, requiring higher dosage and more continuous use of medications. As a result, many patients whose pain was initially well controlled with medication find they must increase to toxic levels in order to control their pain. At this point, unless they are willing to exist with the pain or be in a toxic state, they require surgical intervention. The trigeminal nerve consists of three branches:

V1-Ophthalamic.  This is the first branch of the TN nerve and provides feeling to the forehead, eye and nose.

V2 – Maxillary.  The second branch of the TN nerve and it is responsible for supplying feeling to the lower eye, cheek and upper teeth and the side of the nose.

V3 – Mandibular.  The third branch of the TN is responsible for sensation to the lower teeth and gums and the jaw. 

The initial treatment for Trigeminal Neuralgia should be medical. The most common drugs are:

• Carbamazepine (Tegretol®)
• Gabapentin (Neurontin®).

• Phenytoin (Dilantin®)

• Oxcarbazepine( Trileptal®)

• Gabapentin (Lyrica ®)

   

They should be started at a low dose and gradually increased with the ideal dosage being that which controls the pain but does not cause side effects. The actual amount is different for each person.  It is not uncommon for a patient to be on more than one drug at a time or a “cocktail”.  In some cases a combination of the drugs works better than a single one at a higher dosage.  The muscle relaxant Baclofen has also been used in combination with the anti convulsants as it may add to the effectiveness of the drug. 

It is important for the patient to work closely with their physician in finding the right combination and/or dosage in managing their pain.  Keeping a diary of how the drugs make you feel initially, and as the dosage increases, the side effects etc is an effective way in relaying this important information to the physician. 

If during therapy the pain subsides completely for four weeks, it is reasonable to gradually reduce the dosage and see if the Trigeminal Neuralgia has gone into remission. If the pain recurs the drug can be re-instituted.

For those patients whose symptoms cannot be controlled medically without side effects or who desire long term relief without medication, there are surgical options available. The surgical options can be divided into two categories: non-destructive procedures and destructive procedures. 

Non-Destructive Procedures

The most evasive of all the surgical options but also the only non-destructive procedure for Trigeminal Neuralgia is Microvascular Decompression (MVD).  This procedure involves a few days stay in the hospital.  MVD is preformed under general anesthesia.  The neurosurgeon makes a small opening in the skull just behind the ear to expose the trigeminal nerve and using a microscope to visualize the junction where the Trigeminal nerve enters the base of the brain.  This is the most common area that a blood vessel is usually fond compressing the nerve.  The blood vessel is moved away from the nerve and tiny implants of Teflon® felt are place between the vessel and the nerve.  If it is a vein compression the nerve and it is viable to do so the surgeon may cauterize the vein instead of using the Teflon® felt.

In the majority of patients immediate pain relief without numbness is the advantage of this surgery.  95-98% of patients will awaken from surgery pain free.  However, as in all surgeries there are risks of side effects and some patients do experience facial numbness but to a much lesser degree than the destructive procedures produce.

 Destructive Procedures

There are multiple destructive procedures which are beneficial in the treatment of Trigeminal Neuralgia. The most common of which are:

• Glycerol Injections – “Under sedation the doctor inserts a needle through the cheek and into an opening at the skull base.  The doctor injects a small of amount of sterile glycerol into the small sac of spinal fluid that surrounds the trigeminal nerve ganglion and part of the root.  This chemically damages the nerve fibers.  Pain relief is immediate however many experience mild to moderate facial numbness.  This is an outpatient procedure.

• Electrocoagulation (radiofrequency) Also under anesthesia a needle is passed through the cheek.  However for this procedure the patient is awakened and the doctor will pass a small electric current through the needle which causes tingling.  When it is in the area of the TN pain the patient is once again sedated and then that portion of the nerve is gradually heated with an electrode.  As with the Glycerol injection the heating of the nerve damages the nerve fibers.  This is an outpatient procedure.  Pain relief is immediate and numbness of the face may be a side effect.

• Balloon compression.  Under general anesthesia a needle is passed through the face.  Once in the correct position a small thin catheter with a balloon on the end is threaded through the needle.  The needle is inflated with enough pressure to damage the nerve and block the pain signals.  Pain relief is almost immediate.  Some facial numbness may occur and temporary weakness in the muscles for chewing may be experienced.  Balloon compression is generally an outpatient procedure however in some cases there may be an over night stay in the hospital.

• Gamma Knife Radiation   This surgery focuses 201 separate beams of radiation at the trigeminal nerve root in order to damage the nerve and block pain signals.  A metal frame is attached to the patient's head and then an MRI is taken.  Once the doctors have calculated the exact spot the patient is positioned into the Gamma Knife machine.  The surgery is performed without the need of general anesthesia.  However patients may request a sedative if they feel claustrophobic. 

ain Pain relief is not immediate and it may take weeks to months before the patient feels the full benefit of the surgery.  Numbness in the face is a possible side effect and the full side effect of the radiation used is still being studied.  The Gamma Knife treatment is performed as an outpatient usually.  In some cases an over night stay in the hospital may be required.

These procedures are all based on interrupting the pain by partially damaging the Trigeminal nerve fibers.  Generally the more numbness produced, the longer the pain relief will last.

 Note the picture of Valerie during her Gamma Knife Procedure